Gut Bacteria and Their Hidden Viruses: A Surprising Discovery

In the world of tiny organisms living in our gut, there's a lot going on. One such organism is the bacterium Desulfovibrio piger. It's found in both healthy people and those with inflammatory conditions. This makes scientists wonder what role it plays in our health. Researchers studied three new strains of D. piger from healthy people and one strain from a person with ulcerative colitis. They found that the genomes of these bacteria are quite different. One strain, FI11455, had a larger genome than the others. It also had a big piece of DNA called a megaplasmid. This megaplasmid had a section that looked very similar to the main DNA of another strain, FI11311. This suggests that genes can move around between different parts of the bacterium's DNA. Each strain of D. piger had four to five viruses, called prophages, hidden in their DNA. These prophages were different from any known viruses. They had genes for various functions, including replication, regulation, and structural proteins. Some of these genes were similar to a type of virus called Mu-like proteins. The researchers found that these prophages can be released from the bacteria. They used a chemical called mitomycin C to induce this release and saw virus particles under a microscope. Interestingly, they also saw spontaneous release of these viruses without any induction. This is the first time this has been observed in gut-associated Desulfovibrio bacteria. The implications of this discovery are significant. It suggests that these viruses can transfer genes between bacteria in the gut. This could have important consequences for the gut microbiome and overall health.